The neurophysiologic developmental sequence leading to successful oral feeding remains poorly delineated in the preterm infant largely because there are no objective measures of the sensorineural pathways involved in oromotor function. The long term goal of this research is to describe the maturation of perioral sensorimotor function of the preterm infant using a new methodology, which has the potential for application in the assessment of neurodevelopmental integrity of the preterm infant, as well as for the development of specific interventions. We propose to use the mechanically evoked perioral reflex responses combined with functional assessment of sucking to test the following hypotheses: 1) An organized ontologic sequence of neurophysiologic perioral reflexes and oromotor responses developed in the infant during nonnutritive sucking, dependent upon post conceptual maturation. 2) Delay or aberration in the developmental pattern of perioral reflexes will occur secondary to abnormal external perioral/intraoral stimuli and/or lack of normal stimuli. 3) Injury to the central nervous system in the developing neonate will result in delay or abnormality of the ontogeny of the perioral reflexes. To test these hypotheses electromyographic oromotor measurements will be prospectively obtained in three groups of preterm infants (28 weeks gestation): 1) healthy preterm infants; 2) preterm infants who have experienced prolonged intubation and 3) preterm infants with grades III and IV intraventricular hemorrhage. Functional assessment of sucking will be obtained by measuring the onset of suck, the suck pressure inside the oral cavity and the respiratory cycle in coordination with the suck. Preliminary studies of the oromotor reflexes in early infancy using the proposed methodology indicate highly significant changes in latency and specificity which correlate with maturation. However, perioral neurophysiologic function has not been measured previously using these techniques in the preterm infant. These proposed studies will provide objective, quantifiable information for the first time concerning the development of this critical functional ability. Furthermore, determining sensorimotor reflexes is a novel approach to neurodevelopmental assessment, and may ultimately form the basis for designing specific interventions.